You’re 17 years old. You’ve been living in London as an illegal immigrant for the past two years, having been brought to the UK by your father and left with a friend. It’s a nervous, hand-to-mouth existence, and the closest you get to having companionship and a place to belong is by going along to the Finsbury Park mosque, not so much for the prayers as for the free food and the football. This, in a nutshell, was the life of Sidali Feddag, a young Algerian teenager, until early on the morning of the 5th January 2003, when there was a heavy knock at his door and his world exploded.

Sidali spent the next two and half years in the maximum security prison of Belmarsh (despite being a juvenile), before going on trial at the Old Bailey and being found not guilty of the charges against him. The charges were of terrorism and of conspiracy to murder through the creation and application of ricin. His defence solicitor was Julian Hayes, and it is he who reveals in this carefully-documented accounts the full extent of the government pressure which was brought to bear to maintain the fiction of this ricin ‘poison cell plot’ in order to justify the US and UK invasion of Iraq a very few months later.

Colin Powell, in his address to the UN calling for support for coalition forces in attacking Iraq and forcing ‘regime change’, used this so-called plot as a key part of his argument. Tony Blair regarded it as the ‘silver bullet’ which would justify committing British forces to the invasion. Donald Rumsfeld, George W. Bush, David Blunkett and countless others all told and re-told the story of this terrorist conspiracy, linking it to the deadly danger they claimed Saddam Hussein posed to the western world.

There was no ricin, there was no conspiracy, Sidali and his co-defendants were no terrorists.

In one way this is a straightforward David and Goliath story, with the defence teams battling the huge pressure brought to bear on the police, the prosecution, the judiciary and the witnesses by those in the very highest positions of power. It took enormous energy, ingenuity and expertise (and some sheer luck) to reveal to the jury the way in which the police had rigged the evidence, the extent to which the Home Office expert witnesses had been coerced into distorting their findings, the possibility that there was an agent provocateur deep at the heart of all that unfolded.

But, fascinating though that is, scrupulously documented here and revealed in all its shoddy detail, this story is much more than that. Rather than being another all-too familiar tale of political corruption, institutional blindness and vicious anti-Muslim prejudice, The Poison Cell is an affirmation of the power of truth, the strength of the jury system and the robustness of the British judicial process.

Extraordinarily enough, through all the bullying and humiliation and fear, Sidali Feddag, rather than emerging embittered and radicalised, came to be so won over by the British legal system that he has now trained as a lawyer, and is currently practicing in London as a defence solicitor, working with Julian Hayes.